Automated analyzer

ABSTRACT

Stepped portions of a flow channel are reduced by completely fixing the channel that extends to the measuring unit, and reducing connections in the channel, thereby to suppress a disturbance in the flow of the liquid suctioned into the measuring unit. A means is provided so that the reaction solution and reagent suctioned will move towards the channel through which the liquids are suctioned.

This is a continuation application of U.S. Ser. No. 13/145,355, filedAug. 1, 2011, which is a 371 of PCT Application No. PCT/JP2010/000212,filed Jan. 18, 2010 and claims priority to JP 2009-017462, filed Jan.29, 2009. The entire disclosures of all of these applications are herebyincorporated by reference.

TECHNICAL FIELD

The present invention relates to clinical examination and chemicalanalysis, and more particularly, to an automated analyzer that usesmagnetic particles during analysis.

BACKGROUND ART

During immunoassay that uses a flow cell, automated analyzers, inparticular, that employ magnetic particles quantitatively analyzeconstituents of a substance to be measured, by causing antigen-antibodyreactions in a liquid mixture of a sample, magnetic particles, anantibody that binds the magnetic particles to a substance in the samplethat is to be measured, and a labeled antibody including a labeledsubstance.

To ensure that constituents not to be measured are removed from theliquid mixture (hereinafter, referred to as the reaction solution) thatcontains the constituents to be measured, the magnetic particles, andthe labeled substance, a magnetic separator such as a magnet is providedon a flow channel through which the reaction solution flows.

Because of their binding to the magnetic particles, the constituents tobe measured are captured by the magnetic separator, but the constituentsnot to be measured flow intact without being captured. The constituentsto be measured can therefore be separated from those which are not to bemeasured.

When a voltage is applied to the thus-separated constituents to bemeasured, the labeled substance that has bound to each of theseconstituents will emit light, so the quantity of constituents to bemeasured can be determined by measuring the amount of light emitted.Such an analyzer is described in Patent Document 1, for example.

PRIOR ART LITERATURE Patent Document

Patent Document 1: JP-A-11-258237

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

Conventional immunoanalyzers have adopted a scheme in which a reactionsolution and a reagent are placed in predefined positions and a nozzlefor suctioning the liquids is moved to a predefined position.Constituent elements of the flow channel from a general nozzle structureto a measuring unit (flow cell) are as follows:

A metallic or any other form of nozzle free of deformation, ashape-variable tube connecting to the nozzle, a metallictemperature-control pipe connecting to the shape-variable tube, ashape-variable tube connecting to the temperature-control pipe, and aflow cell connecting to the latter shape-variable tube.

In the channel configuration, four channel connections exist: betweenthe nozzle and the former shape-variable tube, between the formershape-variable tube and the temperature-control pipe, between thetemperature-control pipe and the latter shape-variable tube, and betweenthe latter shape-variable tube and the flow cell.

Channel connections are very difficult to completely match in channelinside diameter because of a fabrication error, and thus, theseconnections are usually stepped. The flow of the liquid is disturbed atthe steps, and more particularly for a reaction solution that containsmagnetic particles, the magnetic particles stop flowing at the steps andstay thereat or the flow of the particles is temporarily interruptedthereat. Additionally, these dwelling magnetic particles are pushed in adownstream direction by the flow of the liquid from an upstreamdirection and irregularly break away from the steps. It has been likely,therefore, that for example, if, during measurement of the sample,dwelling constituents of the reaction solution which was measured duringthe previous operation break away and begin to flow again, measurementerrors due to a carryover will occur under the particular measuringconditions.

In addition, the nozzle itself that forms part of the channel hasfrequently moved to suction the reaction solution and the reagent, andduring the movement, the shape-variable tube connected to the nozzlechanges the shape to bend or expand/contract. Under specific conditions,this has likely to cause the problems that a change in the insidediameter of the tube during the measurement changes the state of theflow, that the flow of the magnetic particles is interrupted at bends,or that a smooth flow of the liquid in the channel is impeded byvibration during the movement of the nozzle.

Even if the nozzle suctions a reaction solution that contains magneticparticles of a uniformly dispersing nature, the presence of thedifferences in height between the channel connections and the occurrenceof changes in channel state will cause nonuniform dispersion of themagnetic particles in the channel. Thus, when the magnetic particles arecaptured using magnetic separation means, the particles will not becapturable onto a capturing surface at a uniform magnetic-particlesconcentration, and even when light is emitted by applying a voltage, theamount of light detected will decrease in reproducibility. It is,therefore, desirable that the channel from the nozzle to the measuringunit be free of steps, smooth, and stable in channel state.

An object of the present invention is to provide an immunoanalyzer inwhich a measuring channel through which a reaction solution flows duringmeasurement is free from deformation, bending, andexpansion/contraction, the measuring channel being further constructedto implement uniform dispersion of constituents of the reaction solutionin the channel.

Means for Solving the Problems

An automated analyzer configuration according to claim 1 of the presentinvention for achieving the above object is described below.

The automated analyzer comprises: a nozzle for suctioning a reactionsolution generated by mixing a sample, magnetic particles, an antibodythat binds the magnetic particles to a substance in the sample that isto be measured, and a labeled antibody including a labeled substance;magnetic separation means for capturing magnetic constituents containedin a reaction solution suctioned by the nozzle, in such a manner thatonly the magnetic constituents are captured to separate magneticconstituents and nonmagnetic constituents from each other; and ameasuring unit for quantitatively determining the magnetic constituentscaptured by the magnetic separation means; wherein the nozzle isdirectly connected to the measuring unit.

In contrast to a conventional analyzer in which a shape-variable tubehas been connected between a nozzle and a measuring unit duringimmunoassay with magnetic particles, the automated analyzer according toclaim 1 is of a structure in which the nozzle and the measuring unit aredirectly interconnected so that a flow channel extending to themeasuring unit maintains an original shape during measurement.

While the nozzle and measuring unit here may be integrally formed or mayhave a shape with both interconnected after being formed separately, aboundary between the nozzle and the measuring unit is desirablyconnected smoothly without a difference in height.

A reaction vessel that accommodates the reaction solution containing thesubstance to be measured, and a reagent vessel that accommodates thereagent required for the analysis are placed directly under the fixednozzle. The nozzle sequentially suctions the reaction solution and thereagent and sends both to the measuring unit. Of the reaction solutionthat has been sent to the measuring unit, only the magnetic constituentscontaining the substance to be measured are captured by the magneticseparation means and the nonmagnetic constituents are washed away by thereagent. In addition, after the measurement, another reagent issuctioned by the nozzle and completely washes away the magneticconstituents left in the measuring unit, thereby to get the measuringunit ready for next measuring operation.

The flow channel in this region is completely fixed and has a smoothlyworked inner surface, so the reaction solution in both the channel andthe measuring unit flows uniformly. Around the measuring unit, amagnetic separator that applies magnetism to the reaction solution isdisposed to separate the constituents-to-be-measured that were bound tothe magnetic particles from the reaction solution.

The magnetic separator may use a permanent magnet or any other suitableelement for generating magnetism.

Applying the magnetic separator to the uniform flow of the reactionsolution increases reproducibility of the measurement since magneticparticles stick to a capturing surface uniformly.

Effects of the Invention

As described above, according to the present invention, these featuresand characteristics ensure a stable flow in the measuring unit, even formagnetic particles whose flow is prone to interruptions or nonuniformityin a small-diameter channel, and reduce carryovers and nonuniformity ofdata analytical results.

Improvement of measurement results in reproducibility and in accuracy isthus anticipated.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustrative diagram showing a basic configuration ofmeasuring unit periphery and a reaction solution/reagent transportmechanism;

FIG. 1-A is an external view that shows connection of a flow cell and anozzle;

FIG. 1-B is a sectional view that shows the connection of the flow celland the nozzle;

FIG. 2 is an external view of the reaction solution/reagent transportmechanism;

FIG. 3-1 is a plan view of an automated analyzer, showing reactionvessel loading into/unloading from a reaction disk;

FIG. 3-2 is another plan view of the automated analyzer, showingreaction vessel loading into/unloading from the reactionsolution/reagent transport mechanism;

FIG. 3-3 is yet another plan view of the automated analyzer, showing areaction solution suctioning position;

FIG. 3-4 is a further plan view of the automated analyzer, showing acleaning position for the nozzle;

FIG. 3-5 is a further plan view of the automated analyzer, showing asuction position for reagent (a) and a supply position for reagent (b);

FIG. 3-6 is a further plan view of the automated analyzer, showing asuction position for reagent (b) and a supply position for reagent (a);and

FIG. 3-7 is a further plan view of the automated analyzer, showing acleaning liquid suction position;

MODE FOR CARRYING OUT THE INVENTION

A nozzle is directed downward and connected directly to a flow cell. Areaction vessel for accommodating a reaction solution, reagent vesselseach for accommodating a reagent, and other tools and appliancesabsolutely necessary for analysis are arranged on one surface, and thenthese articles are sequentially moved to a horizontal position directlyunder the nozzle. After this, each article is moved upward for thereaction solution and the reagents to be suctioned through the nozzleinto the flow cell for measurement.

An embodiment of the present invention will be described hereunder usingthe accompanying drawings.

FIG. 1 shows a basic configuration of the present invention. A reactionsolution 102 that contains a substance to be measured and magneticparticles each bound onto the substance, a reaction vessel 101 thataccommodates the reaction solution 102, two kinds of reagents, (a) 105and (b) 106, that are likewise necessary for measurement, reagentvessels (a) 103 and (b) 104 that accommodate the reagents (a) 105 and(b) 106, respectively, and a retainer 107 that retains the reactionvessel 101 and the reagent vessels (a) 103 and (b) 104, are basicconstituent elements of a reaction solution/reagent transport mechanism.A flow cell 108, a nozzle 109 that connects to the flow cell 108, a tube110 connected to the flow cell 108, and a syringe 111 connected to thetube 110 are basic constituent elements of measuring unit periphery. Aregion from the nozzle 109 to the syringe 111 forms one flow channel.The reaction solution/reagent transport mechanism has a horizontaltransport mechanism 401 that moves the retainer 107 rotationally orlinearly in a horizontal plane and a vertical transport mechanism 402that move the retainer 107 vertically. The reaction solution/reagenttransport mechanism moves the reaction solution 102 or reagent (a) 105,(b) 106 retained by the retainer 107, to the nozzle 109 in appropriatetiming according to a particular measuring sequence. By suctioning thereaction solution 102 or the reagent (a) 105, (b) 106 using the nozzle109 and syringe 111, the liquid moves to the flow cell 108. During thesuctioning of the reaction solution 102, a magnetic separation meanscaptures, inside the flow cell 108, a reaction product that includes themagnetic particles contained in the reaction solution 102. Applying avoltage to the captured reaction product makes the reaction product emitlight. The amount of light emitted is detected by a photomultiplier(PMT) 112, so that the quantity of substance under measurement isdetermined. For more stable measurement results, it is desirable thatwhen the magnetic separation means captures the reaction product insidethe flow cell 108, the reaction product be captured uniformly onto acapturing surface. This can be performed by completely fixing thechannel and reducing its connections. More specifically, the reactionproduct having a uniform concentration in the reaction solution 102 canbe suctioned onto the internal capturing surface of the flow cell 108without flow interruptions due to reasons such as a change in a shape ofthe channel or presence of steps between the connections, and maintainthe uniform concentration. FIG. 1 shows an example in which the channelfrom the nozzle 109 to the flow cell 108 is completely fixed, but aconnection is present in one place. In the present embodiment, the flowcell 108 and the nozzle 109 are formed as separate components to allowfor ease in manufacture and maintainability (including nozzlereplaceability and flow cell replaceability). An external view of theinterconnected flow cell 108 and nozzle 109 is shown in FIG. 1-Aincluding an inlet flow channel 108 a and an outlet flow channel 108 b.A sectional view of the interconnected flow cell 108 and nozzle 109 isshown in FIG. 1-B. The connection between the flow cell and the nozzlecan be removed by integrating both into a single unit. Complete removalof the connection creates a more stable flow during suctioning. Inaddition, carryovers to next measurement are further reduced.

FIG. 2 is an external view of the reaction solution/reagent transportmechanism 200 of the present invention. The reaction solution/reagenttransport mechanism 200 is disposed directly under the nozzle 109connected to the measuring unit, and has mounting regions for thereaction vessel 101 and reagent vessels (a) 103, (b) 104, and for anozzle-cleaning unit 201 in the retainer 107. Horizontal rotation of theretainer 107 in the appropriate timing according to the particularmeasuring sequence moves the mounting regions for the reaction vessel101 and other elements to a position directly below the nozzle 109.After this, the retainer 107 moves upward to insert the nozzle 109 intothe reaction vessel 101 or the reagent vessel (a) 103, (b) 104 and makethe nozzle 109 suction the reaction solution 102 or the reagent (a) 105,(b) 106. Additionally after the suctioning of these liquids, the nozzlecleaning unit 201 moves to the position of the nozzle 109 in a similarmanner to the reaction vessel 101 and other elements in appropriatetiming in order to clean the nozzle 109, and jets cleaning water toclean the nozzle 109. In the present embodiment, the retainer 107 hererotates horizontally to move each mounting region within the retainer107 to a position directly underneath the nozzle. The retainer, however,does not absolutely require rotational movement. Instead, the retainer107 may be constructed, for example, to move linearly arranged mountingregions to a position directly below the nozzle 109, by linear,horizontal movement. In addition, while the present embodiment uses onemovable retainer 107 to retain the reaction vessel 101, the reagentvessels (a) 103, (b) 104, and the nozzle cleaning unit 201, since themounting regions for the reaction vessel 101 and other elements needonly to be moved to the nozzle 109, the present invention can include aplurality of retainers 107 accessible to the nozzle 109, each of theretainers having one or a plurality of access positions with respect tothe nozzle 109. Furthermore, although the present embodiment uses twokinds of reagents, (a) 105 and (b) 106, mounting locations for otheradditional reagents or the like may be provided according to particularneeds. The present embodiment further includes a retaining region for acleaning liquid vessel 203 to hold a channel-cleaning liquid formaintenance of the channel in the measuring unit. This retaining regionis used for periodic (such as, weekly) maintenance and not used duringroutine analysis.

FIGS. 3-1 to 3-7 are plan views that cover periphery of the reactionsolution/reagent transport mechanism 200 of the present invention, shownin FIG. 2, in examples of application to an automated analyzer 300,showing various stopping positions of the reaction solution/reagenttransport mechanism 200 in rotational directions. In an actualconfiguration, a measuring mechanism 100 is disposed at an upper side ofthe reaction solution/reagent transport mechanism 200. For a betterunderstanding of the drawing, however, illustration of the measuringmechanism 100 is omitted and only the nozzle 109 is shown.

To implement continuous measurement with the automated analyzer 300, thereaction vessel 101 accommodating the reaction solution 102 needsreplacing for each measuring operation. A need also arises to provide anelement that transports to the reaction solution/reagent transportmechanism 200 the reaction vessel 101 accommodating the reactionsolution 102 which has been used for a reaction in a reaction disk 301,and an element that unloads from the reaction solution/reagent transportmechanism 200 the reaction vessel 101 that has been used for themeasuring operation. In the present embodiment, a reaction vesseltransport unit 302 transports the reaction vessel 101 between thereaction disk 301 and the reaction solution/reagent transport mechanism200. The reaction disk 301 itself is of horizontally rotatableconstruction and moves the mounted reaction vessel 101 to a position atwhich the reaction vessel transport unit 302 can remove the reactionvessel 101 from the reaction disk 301. The reaction vessel transportunit 302 includes a device that grips the reaction vessel 101, and adevice that moves the gripping device upward/downward, and has astructure that allows the devices to be moved horizontally. Thesedevices and structure of the reaction vessel transport unit 302 move thereaction vessel 101 between the reaction disk 301 and the reactionsolution/reagent transport mechanism 200, as shown in FIGS. 3-1 and 3-2.

The transported reaction vessel 101 is moved for measurement to theposition shown in FIG. 3-3, and the reaction solution 102 is suctionedby the nozzle 109. In addition, the reagent vessels (a) 103, (b) 104 aremoved in appropriate timing to the positions shown in FIGS. 3-5, 3-6,and the reagents (a) 105, (b) 106 are suctioned by the nozzle 109. Afterthis, in order to remove sticking reaction solution 102 and reagents (a)105, (b) 106 from the nozzle 109, the nozzle 109 is cleaned by movingthe nozzle cleaning unit 201 in appropriate timing as shown in FIG. 3-4.There is a need to supply a new reagent (a) 105 to the reagent vessel(a) 103, and a new reagent (b) 106 to the reagent vessel (b) 104, inappropriate timing in order to avoid a shortage of the reagents (a) 105,(b) 106 consumed during the measurement. The present embodiment includesa reagent supply unit (a) 303 that supplies the reagent (a) 105 to thereagent vessel (a) 103, and a reagent supply unit (b) 304 that suppliesthe reagent (b) 106 to the reagent vessel (b) 104. In the presentembodiment, the reagent (a) 105 is supplied at the position shown inFIG. 3-6, and the reagent (b) 106 at the position shown in FIG. 3-5.

Reagent supply quantities are calculated from the liquid level detectedby a detection function for the liquid level in the reagent vessel, andfrom a cross-sectional area of the reagent vessel.

Known techniques for detecting the liquid level include, for example,the electrical continuity scheme for detecting electrical continuitywhen the nozzle or the like comes into contact with the surface of theliquid, and the capacitance scheme for detecting a change in capacitancewhen the nozzle or the like likewise comes into contact with the liquidsurface. Ultrasonic detection and image-based detection are also known.In the present embodiment, the electrical continuity scheme is employed,in which scheme, an electroconductive electrode 202 is fixed to anelectroconductive retainer 107 and has ends placed in the reagent vessel(a) 103, (b) 104. When the retainer 107 is moved upward, the nozzle 109comes into contact with the liquid surface of the reagent (a) 105 in thereagent vessel (a) 103, as shown in FIG. 3-5, or with the liquid surfaceof the reagent (b) 106 in the reagent vessel (b) 104, as shown in FIG.3-6. Continuity between the nozzle 109 and the retainer 107 then occursto enable the detection of the liquid level. Using an electroconductivematerial to form the reagent vessels (a) 103, (b) 104 with which theelectroconductive retainer 107 is in contact allows continuity to bedetected without the electrode 202, if the nozzle 109 comes into contactwith the liquid surface of the reagent (a) 105 or (b) 106. In addition,if actual reagent consumption is uniform, the liquid level detectionfunction is not always required. Instead, it suffices just to provide anelement that timely adds reagent according to the particularconsumption.

In the present embodiment, analysis is conducted in the following orderof steps, and at several stopping positions, a plurality of steps may beconducted at the same time for more efficient analysis: (1) Transport ofthe reaction vessel 101 (see FIG. 3-2)--->(2) Suctioning of the reactionsolution 102 (see FIG. 3-3)--->(3) Cleaning of the nozzle 109 (see FIG.3-4)--->(4) Transport of the reaction vessel 101 (return to reactiondisk)/Suctioning of the reagent (a) 105/Supply of the reagent (b) (seeFIG. 3-1 or 3-5)--->(5) Measurement--->(6) Suctioning of the reagent (b)106/supply of the reagent (a) (see FIG. 3-6)--->(7) Suctioning of thereagent (a) 105 (see FIG. 3-5)--->(1) Transport of the next reactionvessel 101 (see FIG. 3-2); subsequently, this sequence is repeated.

As described above, the retainer 107 in the reaction solution/reagenttransport mechanism 200 of the present invention has a region in whichto mount the cleaning liquid vessel 203 for holding the channel-cleaningliquid for the maintenance of the channel in the measuring unit. Thechannel in the measuring unit can also be cleaned by moving the reactionsolution/reagent transport mechanism 200 to the position shown in FIG.3-7, and then suctioning from the nozzle 109 the channel-cleaning liquidaccommodated in the cleaning liquid vessel 203.

DESCRIPTION OF REFERENCE NUMERALS

-   100 Measuring unit-   101 Reaction vessel-   102 Reaction solution-   103, 104 Reagent vessels-   105, 106 Reagents-   107 Retainer-   108 Flow cell-   109 Nozzle-   110 Tube-   111 Syringe-   112 PMT (Photomultiplier)-   200 Reaction solution/reagent transport mechanism-   201 Nozzle cleaning unit-   202 Electrode-   203 Cleaning liquid vessel-   300 Automated analyzer-   301 Reaction disk-   302 Reaction vessel transport unit-   303, 304 Reagent supply units-   401 Horizontal transport mechanism-   402 Vertical transport mechanism

The invention claimed is:
 1. An automatic analyzer comprising: a suckingnozzle which sucks a reaction solution which is a mix of a sample,magnetic particles, an antibody that binds the magnetic particles to asubstance in the sample that is to be measured, and a labeled antibodyincluding a labeled substance; a retainer having a plurality of mountingregions on which a plurality of reaction vessels are placed, and thereaction solution is held by one of the reaction vessels; a horizontaltransport mechanism which moves the retainer in a horizontal plane totransport the one of the reaction vessels to a first position below thesucking nozzle; and a vertical transport mechanism which moves theretainer in a vertical direction to transport the one of the reactionvessels from the first position to a second position where the suckingnozzle is inserted into the one of the reaction vessels and sucks thereaction solution from the one of the reaction vessels; a flow cellhaving an inlet flow channel, an outlet flow channel and a capturesurface to store the reaction solution sucked from the sucking nozzletherein; a magnet disposed to capture the substance combined withmagnetic particles contained in the reaction solution on the capturesurface of the flow cell; and a detector which quantitatively measuresthe reaction solution captured on the capture surface of the flow cell,wherein the inlet flow channel, the outlet flow channel and the capturesurface are disposed on a bottom surface of the flow cell, wherein thedetector is disposed above a top surface of the flow cell, wherein thesucking nozzle is directly connected to the inlet flow channel to definea linear flow path from a tip of the sucking nozzle to the inlet flowchannel, and wherein both the sucking nozzle and the flow cell are fixedsuch that they do not move from a time of sucking the reaction solutionthrough a time of capturing the magnetic particles on the capturesurface.
 2. The automatic analyzer of claim 1, wherein the suckingnozzle and the flow cell are formed as separate components, and thesucking nozzle is detachably connected to the inlet flow channel.
 3. Theautomatic analyzer of claim 1, wherein the sucking nozzle and the flowcell are formed as a single unit.
 4. The automatic analyzer of claim 1,wherein the flow cell has a recess around the inlet flow channel toconnect to the sucking nozzle.
 5. The automatic analyzer of claim 1,wherein the sucking nozzle and the flow cell are fixed such that they donot move from a time of sucking the reaction solution through a time ofdetection by the detector.
 6. The automatic analyzer of claim 1, furthercomprising: a syringe which is connected to the outlet flow channel tosuck the reaction solution into the flow cell.